Cloud Formations

Question 1

What are the four main types of clouds?

Answer 1

• cumiliform = flat base that extend upwards, due to air being warmed by warm ground rising then cooling
• stratiform clouds = layers of cloud, due to hot air moving across a cold surface
• cirrus = curls of cloud, due to low water vapour at a high altitude forming ice crystals
• fog, formed through advection which causes a dew point and condensation which is key to the water cycle - mainly in the TRF

Question 2

How do clouds form?

Answer 2

1. Adiabatic expansion = air is pressurised in the parcel = high kinetic energy which produces heat, the air parcel then rises and cools and condenses
2. Orthographic uplift = happens with mountain ranges, as air is forced up the windward side it goes through adiabatic expansion rapidly causing it to condense and release precipitation, as it then drops the surrounding air is cooler so it becomes less pressurised and therefore is dry and warm on the leeward side
3. Fronts = the two fronts (hot and cold air) can’t mix together, makes them drop/rise above the other

Cold advance = forces hot air to rise suddenly as they move quickly, the rapid rise causes extreme pressure and therefore forms cumiliform/cumiliform nimbus

Hot advance = slowly rises over the cool air and goes through adiabatic conensation (usually results in precipitation) and therefore forms stratiform clouds

Question 3

What is adiabatic expansion

Answer 3

Where high pressure pockets cause the particles to interact= high kinetic energy = high pressure, this makes the air rise as it rises the pressure decreases and the air cools

Question 4

absolute humidity vs relative humidity

Answer 4

Absolute = the amount of water an air parcel is able to hold

Relative = the % of water an air parcel is holding

Both are reliant upon temperature

Question 5

What is the ELR

Answer 5

The environmental lapse rate means that for every 1000m increase in altitude the temperature drops by 6.5 degrees

Question 6

What are the two different types of adiabatic expansion

Answer 6

• saturated adiabatic expansion = 7 degree change for every 1000m increase - due to latent heat and condensation keeping the air warmer than the surroundings = absolute instability = cumuliform
• dry adiabatic expansion = 10 degree change for every 1000m increase - as the air is cooler than the surrounding air this causes absolute stability

Question 7

What does nimbus mean

Answer 7

Deep and tall clouds - usually storm clouds